Ko won her third LPGA title, but her first as a member of the tour. She pocketed $270,000 and recorded her fourth top 10 of the season.

Starting the day one shot behind Lewis, Ko evened the score at the turn, but then she dropped a shot at the par-4 10th.

It would be her final mistake of the day.

Ko made three birdies coming in, including a 5-footer for the win on the par-5 18th.

Despite three birdies on the final five holes, it was another disappointing loss for Lewis, who is still searching for her first win since last year's Women's British Open.

Ko's win capped a pretty solid week for the teenager. She turned 17 on Thursday, and she was also named one of the Top 100 Most Influential People by Time magazine. And to top it off, Annika Sorenstam wrote the article in Time, calling Ko, "exceptionally talented, mature beyond her years and well liked by golf fans and competitors alike."